The Most Incredible Sound Rig You Ever.....

Mazeroth

I'm actually going to have to agree with Sid, for once. These guys are putting together, what would seem like, a killer system. But...well...they're in for a rude awakening.

I've frequented the popular DiY speaker sites for the last 18 months, but for the last 10 months I've researched nothing but dipole speakers and finally feel ready to build a pair of my own, now that I totally comprehend how they work. Having more than two sources (stereo) for anything under 80hz in a dipole setup is just plain ridiculous. The amount of cancellations that are going to occur in this guy's setup are going to make the whole install moot. He'll need so much equalization that it will pretty much make it worthless.

The way dipole speakers work is that it's dependant on the effective path difference of the front wave to the rear wave to determine when cancellations will occur. If you have an 18" wide baffle and the woofer is mounted in the middle, you have 9" to the sides, say 1" back, and 9" to the center of the rear baffle, which equates to a 19" path difference. The larger the path difference, the lower in hz. cancellations will begin to occur. This is what Troy was stating when the cancellations occur at a 90 degree angle. This is true for the baffle, but when it comes to the rear wave and front wave meeting up later for lunch, well, that's when you have issues.

Picture yourself sitting in the middle of this Carver Amazing listening room. You are surrounded by large panels flanked with 12" woofers and long, sexy planar transducers. Now, try to draw a picture in your mind of the woofers' radiation pattern from the speaker, reflecting off the walls, and reaching you. Did you draw two radiation patterns for each speaker? If you didn't, go back and do so If you thought the first drawing in your mind was complicated, now you just introduced twice as many waves. When these in and out of phase signals meet up with each other, you are going to have nulls like you couldn't believe. Nulls aren't nearly as bad when you're talking about monopolar speakers, but in this case, with the dipolar radiation, it is. Harman published a few white papers that a lot of the DiY community revert back to (don't have the link handy) that goes in to great detail the placement of low frequency transducers in a room and that any more than two makes things get real ugly, real fast. The same thing applies here. Turns out it's best to have your low frequency transducers in the middle of the side walls, where you might have thought having one in each corner would be best, which turns out to be just about as bad as you can get.

Another problem with their implementation is going with two speakers per channel. Unless they are going to put them on top of each other (highly doubt this) they are really going to screw things up. The planar membranes used in the amazings have extreme horizontal dispersion, and once the two waves meet, which should only take a few feet, they're going to cancel each other out in the effect of about 12db, increasing as frequency increases. To make matters worse, these also have a dipolar radiation pattern, so, yeah, not good.

One last thing before I hit the sack. As far as dipoles having a huge, open soundstage, that's not the reason why they're superior to monopolar speakers. The reason is because of the lack of room modes excited by a dipolar radiation pattern (basically non existant) and the lack of mechanical force exerted back on the driver from the rear wave, which leads to minimal distortion, at the price of lowered power handling and the requirement for equalization. When you lower distortion you are effectively making a speaker "more accurate", allowing it to reproduce the signal more cleanly. Placing a dipole speaker close to the side walls doesn't matter much, due to the cancellations at 90 degrees, which usually happen at the edge of the baffle. However, placing them too close to the back wall will create a "more wide/opened soundstage", which should actually be avoided. A lot of people like this, and I am one of them, but if you ask or read Sigfried Linkwitz's website you will see this is not a desirable configuration for accurate music reproduction. Linkwizt is THE AUTHORITY when it comes to dipole speakers, so if you're interested in learning more, check out these links:

http://linkwitzlab.com/frontiers_4.htm
http://linkwitzlab.com/rooms.htm

Here's a link to the Linkwitz Orion speaker, which is very similar to the speaker I'm designing, in case you guys give two rats:
http://linkwitzlab.com/orion_us.htm

If these two were truly were professional sound guys I highly doubt they would attempt something like this. I will commend them on having great aspirations and I wish them the best, but I could think of much better things to waste, errr spend, my money on

TroyD

My point was/is that not that I think it would be a breeze, but Sid's assumptions were based on faulty logic. Again, I'm not saying that I'm anywhere NEAR an expert on this subject but, again, it's a doable thing.

Major tired head on this....

http://www.audiodesignguide.com/mag/tech2.html

Good read on the design of the Amazing. Explains it far better than I.....

BDT

Tour2ma

Troy,
And you said you didn't care...

Was I the only reading Post #1 and waiting for GG to type, "... and then guns were drawn and ..."?

As for the proposed system, pure overkill. So what's not to love?

jdhdiggs

Maz, you're still thinking too few waves. With as many as they have, cancellations will more than likely be made up for by re-enforecment from other speakers. Beacuse of the shear number of drivers and such, the system should clean itself.

I wish I could find the article on subs but it said, in a nutshell, if you could get more than 16 drivers in any room, room modes become a mute point and that the best setup would entail infinate drivers, not 1. These guys are setting up 56 dipole drivers. Sounds like things should take care of themselves.

Mazeroth

Not too few waves. When you have speakers close to each other they form somewhat of a coupling effect. It's the position in the room that matters. Putting 16 speakers in a room in one spot isn't going to negate any room modes, but it will cause some enormous cancellations. Also, even though the Amazings have multiple 12" woofers, they still count as one because in that configuration they are a line source, which throws its sound in a single continuous wavefront.

TroyD

35'x34' w/ 10' ceilings?? I'd say that it's possible that they will be fairly well spread out.....

BDT